Bring a medium saucepan of water to a boil and salt it generously. 2.
While the water heats, melt 3 tablespoons (45 ml / 1.5 fl oz) of butter in a large, deep skillet or casserole with a tight-fitting lid over medium heat. 3.
Add the rice to the boiling water and cook, stirring occasionally, for about 5 minutes, just until it loses its raw translucence.
Drain the rice well, leaving it a little wet. 4.
Add the sliced onions to the melted butter along with a large pinch of salt and some pepper.
Cook, stirring occasionally, for about 5 minutes until the onions just begin to soften. 5.
Add the drained rice to the onions, along with the saffron threads if using.
Stir to combine everything, then turn the heat to the absolute minimum and cover the pan. 6.
Cook for about 45 minutes, stirring every 15 minutes or so to prevent sticking. For the final 10-15 minutes, do not stir to allow a delicious golden-brown crust to form on the bottom. 7.
Check that the onions are very soft and the rice is fully cooked.
Taste and adjust seasoning with more salt and pepper.
Stir in the heavy cream and/or any remaining butter if you desire extra richness.
Heat through gently. 8.
Turn off the heat and let the dish rest, covered, for at least 10 minutes before serving.
Garnish with fresh parsley and enjoy.
Don't skip the final resting period. This allows the flavors to meld and the rice to absorb any final moisture, resulting in a perfect texture.
